Posted by Erwin Moller on 08/30/07 09:25

Erwin Moller wrote:
> Erwin Moller wrote:
>> Defacta wrote:
>>> Hi,
>>>
>>> When I upload an excel file, PHP does not recognize the type of this
>>> file:
>>>
>>> echo $HTTP_POST_FILES['file']['type'] ;
>>>
>>> returns: application/octet-stream
>>> Whereas a word file returns: application/msword
>>>
>>> Do you know if there is anyway to get the type of a excel file ?
>>>
>>> Thanks,
>>> Vincent.
>>>
>>
>> Hi Vincent,
>>
>> From http://nl3.php.net/manual/en/features.file-upload.php
>>
>> ------------------------------------------------------------------------
>> $_FILES['userfile']['type']
>>
>> The mime type of the file, if the browser provided this
>> information. An example would be "image/gif". This mime type is
>> however not checked on the PHP side and therefore don't take its value
>> for granted.
>> ------------------------------------------------------------------------
>>
>> Bottomline: don't rely on this.
>> And the value application/octet-stream just means it is a binary file,
>> which is correct in this case, but little informative.
>
> Forgot to mention:
> When I am in the situation my script must decide WHAT the file is, I
> always use the extension to make my best guess.
> But it is stays a guess.
> You can never make this 100% foolproof.
> If you upload a MS Word document to my Linux (Debian) server, I have no
> way of checking what it is. I cannot open it for example.
> You could rename your mydoc.pdf to mydoc.gif or mydoc.doc.
>
> There ARE a few things you can check on a nix server to extract the
> filetype, but it cannot handle all.
>
> Here is a piece of code I use in some situation (*nix only)
>
> if (!function_exists('mime_content_type')) {
> function mime_content_type($f) {
> $f = escapeshellarg($f);
> return trim( `file -bi $f` );
> }
> }
>
> and then call it like:
> $probablemime = mime_content_type($yourfile);
>
> where $yourfile must be a real file. Not just the name as handed to you
> via $_FILES[] but the file itself. You can use it on the temporary
> stored file before moving it.
>
> Hope that helps a bit.
>
> Regards,
> Erwin Moller

One last addition:
If you want to use PECL, have a look at:
http://nl3.php.net/manual/en/ref.fileinfo.php

php.net claims it does a very good job.
I never used it though...


Regards,
Erwin Moller

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